Final answer:
The appropriate verb to fill in the blank is 'comieron', which is the past tense of the verb 'comer' meaning 'to eat'.
Step-by-step explanation:
The appropriate verb to fill in the blank in the sentence is comieron.
It isthe past tense of the verb 'comer' which means 'to eat'. Since the sentence mentions 'Ayer' (Yesterday), the past tense is used to convey that Juan and Alberto ate with their parents yesterday.
Example: Ayer, Juan y Alberto comieron con sus papás. (Yesterday, Juan and Alberto ate with their parents.)
Learn more about Verb conjugation in Spanish